Partial water change and vacuuming: always necessary?

[Armand61685]

Is it always necessary to change the water partially and vacuum even if the water condition tests fine? I mean, why fix it if it isn't broke?

[quenton]

There are a number of reasons

1. if you change regularly you will stabalize the parameters since changes are cut in 1/2 (if you change 50%)
2. there are things you do NOT test for and they can accumulate, by changing regularly you also stabalize those things
3. you will find that your water appears clearer -- you discard 1/2 of anything that makes your water a bit murky
4. why not do it -- its simple and cheap

[reptileguy2727]

more water changes generally equate to better growth and overall condition. it doesnt hurt and has numerous benefits. when people do water changes properly, they usually notice a very apparent in the appearance of the water as well as an improvement in the fish. they may seem fine without the water changes, but they will do even better with them. it may not seem broken yet, but with fish by the time it is apparrently broken, the tank is too far gone to save everybody. its kind of like preventative maintenance on a car. if you never change the oil, it wont be 'broken' until it is very broken. you save money, stress, and time if you just do the preventative maintenance.

[Armand61685]

ok, cool. So, how often do you guys recommend changing a, let's say, 200 gallon rectangular pond? We just installed a pond in our backyard, it's been 2 weeks, everything is just fine.

Thanks.